Figure 1

Plain radiography and histological findings of primary osteosarcoma. (a) Anteroposterior and (b) lateral radiographs show a central osteolytic lesion with partial ossification in the region from the proximal tibial epiphysis to the metaphysis. (c) Microscopic examination of the biopsy specimen revealed atypical spindle-shaped tumor cells and multi-nucleated osteoclast-like giant cells associated with a neoplastic osteoid formation in the interstitial tissue.